An atmospheric, medieval-themed book store hides in a 13th-century underground space.

One woman's decades-long obsession with the "La Fée Verte."

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

Notorious artist squat renovated into legal studios.

One of the last umbrella repair shops in Paris upholds the nostalgic art of umbrella making.

An unusual number plate signifies the building's saucy past.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

Inside a former cabaret, seven floors of erotic art.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

A Belle Epoque bordello turned into a themed love hotel.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

This Parisian café sticks almost exclusively to an ethos of reuse.

At the foot of a waterfall lies a peaceful swimming lagoon and evidence of over 60,000 years of human habitation.

Village situated on a narrow volcanic escarpment.

This semi-secret storybook hedge maze is also the oldest garden in the city.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Week-long block party becomes a competition for the best decorated street.

The studio of Catalonia's most famous theatrical designer remains exactly as he left it.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.